CN104103650A - Optical module, method of manufacturing the same, and electronic device including the same - Google Patents

Abstract

The invention relates to an optical module comprising: the device comprises a carrier, a light source, a light detector and a first polarizer. The carrier has a first surface on which the light source and the light detector are deposited. A first polarizer is disposed on the photodetector. The polarization direction of the light emitted from the light source and the polarization direction of the light passing through the first polarizer are substantially perpendicular to each other.

Description

Optical module, manufacturing method thereof, and electronic device including optical module

technical field

The invention relates to an optical module and a manufacturing method thereof. The invention further relates to an electronic device comprising said optical module.

Background technique

An optical module, such as a proximity sensor (Proximity Sensor), can be used to sense objects located near the optical module. The optical module has a light source and an optical sensor. The light detector can receive or sense light emitted by the light source and reflected by external or nearby objects, generally infrared rays, so as to detect the presence of an external approaching object.

Cross talk is the light emitted by the light source and directly or reflected by other media different from the above-mentioned objects to the optical sensor, which is also the noise that causes the sensor to malfunction. In the optical sensing module shown in FIG. 1A , the light-emitting element 11 and the photodetector 12 are covered with a transparent material, and the cover 16 is used to prevent the light emitted by the light-emitting element 11 from directly reaching the photosensitive area 123 of the photodetector 12 . Although the cover body 16 can prevent the light emitted by the light-emitting element 11 from directly reaching the photosensitive area 123, it can be seen from FIG. In addition to the light reflected by the object 140 ), the light reflected by the first surface 131 and the second surface 132 will also be received. In the optical module shown in FIG. 1A , about 80% of the light emitted from the light emitting element 11 becomes a crosstalk signal.

In order to show the phenomenon of crosstalk more clearly, taking FIG. 1B as an example, the boundaries of the range of light emitted from the light-emitting element 11 are marked as C3 and C4, and the boundaries of the range of light reaching the photosensitive area after being reflected by the second surface 132 are D3 and C4. D4. In other words, the light emitted from the light-emitting element and between the lights C3 and C4 may be reflected by the second surface 132 to reach the photosensitive region 123 , forming a part of the main source of crosstalk. In addition, crosstalk-like reflections will also occur on the first surface 131 , and the principle is similar so it will not be repeated here.

The optical module shown in FIG. 1C is similar to the optical module shown in FIG. 1A, except that the second medium 130 may include an infrared absorbing layer 133 on the first surface 131 to absorb reflected light (ie, infrared rays) that will become crosstalk. . In FIG. 1C , although about 4.5% of the light emitted from the light emitting element 11 will become a crosstalk signal, compared with the optical module shown in FIG. 1A , the infrared absorbing layer 133 can relatively greatly reduce the crosstalk. Although the infrared absorbing layer 133 can be formed by screen printing technology, the screen printing technology is relatively prone to pollution, increased process steps, and high cost.

In addition, the use of the cover will increase the size of the optical module and the complexity of the process, thus increasing the cost of manufacturing the optical module.

Contents of the invention

Embodiments of the present invention relate to an optical module. The optical module includes: a carrier, a light source, a photodetector and a first polarizer. The carrier has a first surface. The light source is located on the first surface. A light detector is located on the first surface. The first polarizer is located on the light detector. The polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer.

Another embodiment of the present invention relates to an optical module. The optical module includes: a carrier, a light source, a photodetector and a first polarizer. The carrier has a first surface. The light detector has an upper surface and an optical sensing area on the upper surface. A light detector is located on the first surface. The light source is located on the upper surface. The first polarizer covers the optical sensing area. The polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer.

Another embodiment of the present invention relates to an electronic device. The electronic device includes: an optical module and a light-transmitting plate. The optical module includes: a carrier, a light source, a photodetector and a first polarizer. The carrier has a first surface. The light source is located on the first surface. A light detector is located on the first surface. The first polarizer is located on the light detector. The translucent board has opposite first and second surfaces, and the first surface of the translucent board faces the first surface of the carrier. The polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer.

Another embodiment of the present invention relates to a manufacturing method of an optical module, including: providing a carrier, the carrier has a first surface; placing a photodetector above the first surface; placing a light source above the first surface; and placing the second A polarizer is placed over the photodetector. The polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer.

Another embodiment of the present invention relates to a manufacturing method of an optical module, comprising: providing a carrier, the carrier has a first surface; placing a photodetector on the first surface, the photodetector has an upper surface and is located on the first surface an optical sensing area on the upper surface; placing a light source on the upper surface of the photodetector; and placing a first polarizer on the photodetector and covering the optical sensing area. The polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer.

Description of drawings

1A-1C are schematic diagrams of prior art optical modules.

2A-2D are schematic diagrams of a manufacturing method of an optical module according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of an optical module according to another embodiment of the present invention.

4A-4D are schematic diagrams of a manufacturing method of an optical module according to another embodiment of the present invention.

FIG. 5 is a schematic diagram of an optical module according to another embodiment of the present invention.

FIG. 6 is a schematic diagram of an electronic device according to an embodiment of the invention.

Detailed ways

FIG. 2D is an optical module 20 according to an embodiment of the present invention. Referring to FIG. 2D , the optical module 20 may at least include a carrier 200 , a light source 202 , a light detector 203 , a polarizer 205 and a polarizer 206 .

The carrier 200 has a first surface 201 . Bonding wire pads (not shown) may be disposed on the first surface 201 . The carrier 200 may include a driving circuit (not shown). The bonding wire pads on the first surface 201 can be electrically connected to the driving circuit of the carrier 200 .

The light source 202 and the light detector 203 are located on the first surface 201 . The light source 202 may be, but not limited to, an infrared light emitting diode. The light detector 203 may be, but not limited to, a photodiode that senses infrared rays. In an embodiment of the present invention, the light detector 203 may have an optical sensing region 204 . In another embodiment of the present invention, the light detector 203 may have a plurality of optical sensing regions 204 .

In an embodiment of the present invention, the light source 202 and the light detector 203 can be electrically connected to bonding wire pads (not shown) on the first surface 201 of the carrier 200 via bonding wires 208 . In another embodiment of the present invention, the light source 202 and the photodetector 203 can be electrically connected to the driving circuit of the carrier 200 via bonding wires 208 . The driving circuit included in the carrier 200 can drive the light source 202 to emit light. The driving circuit included in the carrier 200 enables the photodetector 203 to convert the sensed optical signal into an electrical signal.

A polarizer 205 is located on the light source 202 . In the embodiment of the present invention. The polarizer 205 covers at least part of the light source 202 . In another embodiment of the present invention, the polarizer 205 can cover the light emitting area or the light emitting surface of the light source 202 . Therefore, all light emitted from the light source 202 passes through the polarizer 205 .

In an embodiment of the invention, polarizer 206 is located on photodetector 203 . In another embodiment of the present invention, the polarizer 206 may be located on the optical sensing region 204 of the photodetector 203 . In another embodiment of the present invention, the polarizer 206 covers the optical sensing area 204 . Therefore, all light entering the optical sensing region 204 should pass through the polarizer 206 .

The optical module 20 may further include a transparent material 207 . The transparent material 207 can cover at least part of the first surface 201 of the carrier 200 , the light source 202 , the light detector 203 , the polarizer 205 , the polarizer 206 and the bonding wire 208 . The transparent material 207 can protect the components covered by it without affecting the optical properties of the optical module 20 .

In an embodiment, the polarization direction of the light allowed to pass through the polarizer 205 is different from the polarization direction of the light allowed to pass through the polarizer 206 . In another embodiment, the polarization direction of the light allowed by the polarizer 205 and the polarization direction of the light allowed by the polarizer 206 are perpendicular to each other, because the light emitted by the light source 202 should all pass through the polarizer 205, covering the optical sensor. The polarizer 206 of the detection area 204 blocks light directly from the light source 202 from entering the optical sensing area 204 . Therefore, the polarizer 206 covering the optical sensing area 204 will also block the light from the light source 202 and reflected by the transparent material 207 , such as the upper surface 207 a thereof, from entering the optical sensing area 204 . In other words, the combination of the polarizers 205 and 206 of the optical module 20 can block the crosstalk caused by the undesired light. That is, the combination of the polarizers 205 and 206 can prevent the light emitted from the light source 202 from directly reaching the optical sensing region 204 on the photodetector 203 . The polarizers 205 and 206 can also prevent the light emitted from the light source 202 from being reflected by the transparent material 207 , such as the upper surface 207 a thereof, from reaching the optical sensing region 204 on the photodetector 203 .

Referring to FIGS. 2A-2D , FIGS. 2A-2D illustrate a manufacturing method of an optical module according to an embodiment of the present invention.

In FIG. 2A , a carrier 200 is provided, the carrier 200 having a first surface 201 . In an embodiment of the present invention, the carrier 200 may be or include a substrate such as a printed circuit board. The carrier 200 or the first surface 201 of the carrier 200 may include traces, wire-bond pads and/or vias. The carrier 200 may be composed of materials known to those skilled in the art as carriers. For example, the carrier 200 may include materials such as organic materials, polymer materials, silicon, silicon dioxide, or other silicides.

In the embodiment of the present invention, the light source 202 and the light detector 203 can be fixed on the first surface 201 of the carrier 200 by using conductive or non-conductive adhesive. The light source 202 may be, for example, a light emitting diode. The light detector 203 may be, for example, a photodiode. The light detector 203 has an optical sensing area 204 . In an embodiment of the present invention, the optical sensing region 204 may be a part of the upper surface of the light detector 203 . In another embodiment of the present invention, the optical sensing area 204 may have substantially the same size as the upper surface of the light detector 203 . In another embodiment of the present invention, the size of the optical sensing region 204 can vary according to design requirements.

In FIG. 2B , a polarizer 205 may be placed on the light source 202 . A polarizer 205 covers the light source 202 . A polarizer 206 may be placed over the light detector 203 . In an embodiment of the invention, a polarizer 206 covers the optical sensing region 204 .

In an embodiment of the present invention, the polarization direction of the light allowed to pass through the polarizer 205 is different from the polarization direction of the light allowed to pass through the polarizer 206 . In another embodiment of the present invention, the polarization direction of the light allowed by the polarizer 205 and the polarization direction of the light allowed by the polarizer 206 are perpendicular to each other. For example, the polarizer 205 can allow light with a vertical polarization direction (for example: perpendicular to the paper shown in the drawing) to pass through, and the polarizer 206 can allow light with a horizontal polarization direction (for example: parallel to the paper shown in the drawing) pass and vice versa.

In an embodiment of the present invention, the polarizer 205 may allow light with a vertical polarization direction to pass through, and the polarizer 206 may allow light with a horizontal polarization direction to pass through. The light emitted by the light source 202 can only pass through the polarizer 205 with vertical polarization, so the light emitted by the light source 202 may lose half of its intensity when passing through the polarizer 205 . Only light with horizontal polarization can enter the optical sensing region 204 through the polarizer 206 .

In the embodiment of the present invention, the polarizers 205 and 206 can be pasted and fixed on the light source 202 and the optical sensing area 204 respectively by using an adhesive material (not shown in the figure). The glue material can be but not limited to epoxy or silicone.

The polarizers 205 and 206 can be made of heat-resistant materials, for example, high-temperature-resistant metals can be used to form the polarizers 205 and 206 . Because although in the manufacturing process of the optical module 20 (such as the compression molding step described below), the temperature can be as high as 150° C. to 180° C., but because the polarizers 205 and 206 are made of heat-resistant materials, for example, Polatechno ) ProFlux produced by the company? The polarizer is a metal polarizer suitable for infrared polarization with high temperature resistance up to 200° C., so that the deformation or performance damage of the polarizers 205 and 206 can be avoided.

The carrier 200 including the polarizers 205 and 206 may be fixed to other circuit boards or devices using surface mounted technology (SMT). In order to avoid damage to the polarizers 205 and 206 due to excessive temperature in the surface mount technology process, a low-temperature solder paste with an operating temperature lower than 200°C can be used, for example, NC-SNQ81 solder paste produced by Zhongyue Co., Ltd., the highest operating temperature The temperature is lower than 180° C., and the carrier 200 including the polarizers 205 and 206 is fixed to other circuit boards or devices. In other words, the maximum temperature in the SMT process can be controlled below 200° C. to avoid damage to the polarizers 205 and 206 .

In FIG. 2C, the light source 202 and the photodetector 203 are electrically connected to the bonding wire pads on the first surface 201 of the carrier 200 or electrically connected to the driving circuit (not shown in the figure) included in the carrier 200 by using bonding wires 208, respectively. ).

In FIG. 2D , a transparent material 207 is used to cover at least part of the first surface 201 of the carrier 200, the light source 202, the photodetector 203, the polarizer 205, the polarizer 206 and the bonding wire 208 by using a compression molding technique to form an optical module 20. . In an embodiment, the transparent material 207 may be, but not limited to, a transparent encapsulation material including epoxy resin.

In another embodiment of the present invention, multiple, at least one column/row or at least one two-dimensional array (array) of optical modules 20 can be formed simultaneously during the manufacturing process shown in FIGS. 2A-2D . The plurality, at least one column/row or at least one two-dimensional array (array) of optical modules 20 may be diced by singulation to form a plurality of single optical modules 20 as shown in FIG. 2D .

FIG. 3 is an optical module according to another embodiment of the present invention. The optical module 30 disclosed in FIG. 3 is similar to the optical module 20 in FIG. 2D , the difference is that in the optical module 30 , the light source 302 replaces the light source 202 and the polarizer 205 of the optical module 20 . The light source 302 can emit light with a specific polarization direction. In an embodiment of the present invention, the light source 302 may be, for example, an infrared emitting vertical cavity surface emitting laser (VCSEL).

In an embodiment of the present invention, the polarization direction of the light emitted by the light source 302 is different from the polarization direction of the light allowed to pass by the polarizer 206 covering the optical sensing region 204 . In another embodiment of the present invention, the polarization direction of the light emitted by the light source 302 is perpendicular to the polarization direction of the light allowed to pass by the polarizer 206 covering the optical sensing region 204 . For example, the light source 302 emits light with a vertical polarization direction (for example: perpendicular to the paper shown in the drawing), and the polarizer 206 allows light with a horizontal polarization direction (for example: parallel to the paper shown in the drawing) to pass through, and vice versa. Of course.

Since the polarization direction of the light emitted by the light source 302 is perpendicular to the polarization direction of the light allowed by the polarizer 206 covering the optical sensing area 204 , the polarizer 206 blocks the light directly from the light source 302 from entering the optical sensing area 204 . The polarizer 206 also blocks light from the light source 302 and reflected by the transparent material 207 , such as the upper surface 207 a thereof, from entering the optical sensing region 204 . In other words, the polarizer 206 of the optical module 30 can block cross-talk caused by undesired light. That is, the polarizer 206 can prevent the light emitted from the light source 302 from reaching the optical sensing area 204 directly or reflected by the transparent material 207 , such as the upper surface 207 a thereof.

FIG. 4D is an optical module according to another embodiment of the present invention. The optical module 40 disclosed in FIG. 4 is similar to the optical module 20 shown in FIG. 2D, except that in the optical module 40, the light source 202 and the polarizer 205 covering the light source 202 are located on the upper surface of the photodetector 203 instead of the first On a surface 201 , and the light source 202 does not cover the optical sensing region 204 . In the optical module 40 shown in FIG. 4D , since the light source 202 and the polarizer 205 covering the light source 202 are stacked on the upper surface of the photodetector 203 , the size of the optical module 40 can be smaller than that of the optical module 20 . In terms of the cost of the transparent material used for coating, the cost of the optical module 30 may be less than the cost of the optical module 20 .

On the other hand, although the distance between the light source 202 and the optical sensing area 204 is relatively small, since the light source 202 and the optical sensing area 204 are respectively arranged with polarizers 205 and 206, therefore, the area covering the optical sensing area 204 The polarizer 206 blocks light directly from the light source 202 from entering the optical sensing area 204 or blocks light from the light source 202 reflected by the transparent material 207 from entering the optical sensing area 204 . In other words, although the size of the optical module 40 is relatively small, the polarizers 205 and 206 of the optical module 40 can still block unnecessary crosstalk. That is, the light emitted from the light source 202 can be prevented from reaching the optical sensing region 204 directly or reflected by the transparent material 207 .

4A-4D illustrate a manufacturing method of an optical module according to another embodiment of the present invention. In FIG. 4A , a carrier 200 , a light source 202 and a photodetector 203 are provided, each of which can be used as the carrier 200 , light source 202 and photodetector 203 mentioned in the manufacturing method shown in FIGS. 2A-2D . The carrier 200 has a first surface 201 . In the embodiment of the present invention, the photodetector 203 can be fixed on the first surface 201 of the carrier 200 by using conductive or non-conductive adhesive, and the light source 202 can be fixed on the photodetector 203 without covering the optical sensor. District 204 location.

In FIG. 4B , the polarizer 205 is fixed on the light source 202 to cover the light source 202 . A polarizer 206 can be fixed on the optical sensing area 204 of the light detector 203 to cover the optical sensing area 204 .

In the embodiment of the present invention, the step of fixing the polarizers 205 and 206 on the light source 202 and the optical sensing area 204 respectively is to use adhesive materials for bonding and fixing. The adhesive material can be but not limited to epoxy resin or silicone resin.

In FIG. 4C , the light source 202 and the photodetector 203 are electrically connected to the bonding wire pads on the first surface 201 of the carrier 200 or electrically connected to the driving circuit (not shown in the figure) included in the carrier 200 using bonding wires 208, respectively. ).

In FIG. 4D , at least part of the first surface 201 , the light source 202 , the photodetector 203 , the polarizer 205 , the polarizer 206 and the bonding wire 208 of the carrier 200 are coated with a transparent material 207 to form an optical module 40 .

Although not drawn in the drawings, in another embodiment of the present invention, multiple, at least one column/row or at least one two-dimensional array (array) of optical The module 40 is then cut into a plurality of single optical modules 40 as shown in FIG. 4D using cutting technology.

Fig. 5 is an optical module according to another embodiment of the present invention. The optical module 50 disclosed in FIG. 5 is similar to the optical module 40 in FIG. 4D , the difference is that in the optical module 50 , the light source 302 replaces the light source 202 and the polarizer 205 of the optical module 40 . The light source 302 can emit light with a specific polarization direction. In an embodiment of the present invention, the light source 302 may be, for example, an infrared emitting vertical cavity surface emitting laser (VCSEL).

In an embodiment, the polarization direction of the light emitted by the light source 302 is different from the polarization direction of the light allowed to pass by the polarizer 206 . In another embodiment, the polarization direction of the light emitted by the light source 302 is perpendicular to the polarization direction of the light allowed to pass by the polarizer 206 . For example, the light source 302 emits light with a vertical polarization direction (for example: perpendicular to the paper shown in the drawing), and the polarizer 206 allows light with a horizontal polarization direction (for example: parallel to the paper shown in the drawing) to pass through, and vice versa. Of course.

Since the polarization direction of the light emitted by the light source 302 is perpendicular to the polarization direction of the light allowed by the polarizer 206 covering the optical sensing area 204, the polarizer 206 covering the optical sensing area 204 will block the light directly from the light source 302 Enter the optical sensing area 204 or block the light from the light source 302 and reflected by the transparent material 207 , such as the upper surface 207 a thereof, from entering the optical sensing area 204 . In other words, the polarizer 206 of the optical module 50 can block the crosstalk caused by the undesired light, that is, prevent the light emitted from the light source 302 from being reflected directly or through the transparent material 207, such as its upper surface 207a. Reach the optical sensing region 204 .

FIG. 6 is an electronic device according to an embodiment of the invention. Referring to FIG. 6 , the electronic device 6 includes an optical module 60 and a transparent plate 620 .

In the embodiment shown in FIG. 6 , optical module 60 may be or may be similar to optical module 20 shown in FIG. 2D . In another embodiment of the present invention, the optical module 60 may be or may be similar to the optical module 30 , 40 or 50 shown in FIG. 3 , FIG. 4D or FIG. 5 .

The translucent board 620 has a first surface 621 and a second surface 622 opposite to each other. In an embodiment of the present invention, the light-transmitting plate 620 can be, but not limited to, a glass sheet 620 , such as a surface glass of a display screen of a smart phone. The second surface 622 of the glass plate 620 includes a quarter wave plate 623 (1/4λ waveplate). Quarter wave plate 623 may include a birefringent material. The quarter-wave plate 623 can be formed on the second surface 622 by a coating method, for example, the quarter-wave plate is formed by multi-layer coating in a chemical vapor deposition (CVD) process. plate 623, and the finished quarter wave plate 623 can also be directly pasted on the upper surface of the glass 620. In another embodiment, the quarter wave plate 623 can also be formed on the first surface 621 .

In the embodiment of the present invention, when the polarized light enters the quarter-wave plate 623 , the light can be decomposed into vectors of fast axis and slow axis. If the angle between the incident light and the fast axis or the slow axis is 0 degree, then the light exiting the quarter-wave plate 623 has a linear polarization characteristic. If the angle between the incident light and the fast axis and the slow axis is 45 degrees, then the light exiting the quarter-wave plate 623 has a circular polarization characteristic. If the angle between the incident light and the fast or slow axis is 0 to 45 degrees, then the light leaving the quarter-wave plate has elliptically polarized properties.

In an embodiment, the quarter wave plate 623 can change the polarization state of light passing therethrough. Specifically, the quarter-wave plate 623 can change the polarization state of the light emitted from the two surfaces 622 or incident on the second surface 622 . The linearly polarized light entering the light-transmitting plate 620 from the first surface 621 will become circularly polarized light after leaving the light-transmitting plate 620 from the second surface 622 and passing through the quarter-wave plate 623, and vice versa. After passing through the quarter-wave plate 623 , the light will become linearly polarized light when it enters the light-transmitting plate 620 from the second surface 622 .

As shown in FIG. 6 , in the embodiment of the present invention, the light source 202 can at least emit light L ₁ , L ₂ , L ₃ and L ₄ . The polarizer 205 only allows light polarized in the vertical direction (as shown in FIG. 6 , that is, the direction perpendicular to the drawing paper) to pass through. Therefore, the light L ₁ , L ₂ , L ₃ and L ₄ exiting the polarizer 205 is vertically polarized light.

The light L ₁ leaving the polarizer 205 may be reflected by the upper surface of the transparent material 207 into reflected light L ₁ ′. Since the reflected light L ₁ ′ is still vertically polarized light, the polarizer 206 that allows horizontally polarized light (as shown in FIG. 6 , that is, the direction parallel to the drawing paper) to pass through will block the reflected light L ₁ ′ from entering the optical sensor. District 204. In other words, the reflected light L ₁ ′ which should be regarded as noise and not to be sensed cannot pass through the polarizer 206 and enter the optical sensing region 204 to be sensed.

The light L ₂ exiting the polarizer 205 may be reflected by the first surface 621 as reflected light L ₂ ′. Since the reflected light L ₂ ′ is still vertically polarized light, the polarizer 206 that allows the horizontally polarized light to pass through will block the reflected light L ₂ ′ from entering the optical sensing region 204 . In other words, the reflected light L ₂ ′ that should be regarded as noise and not intended to be sensed cannot pass through the polarizer 206 and enter the optical sensing region 204 to be sensed.

The light L ₃ exiting the polarizer 205 may be reflected by the second surface 622 as reflected light L ₃ ′. Since the reflected light L ₃ ′ is still vertically polarized light, the polarizer 206 that allows the horizontally polarized light to pass through will block the reflected light L ₃ ′ from entering the optical sensing region 204 . In other words, the reflected light L ₃ ′ that should be regarded as noise and not intended to be sensed cannot pass through the polarizer 206 and enter the optical sensing region 204 to be sensed.

The light L ₄ exiting the polarizer 205 becomes circularly polarized light L ₄ ′ having a right handedness direction (clockwise direction as shown in FIG. 6 ) after passing through the quarter-wave plate 623 . In other words, after the light L ₄ leaves the second surface 622 and passes through the quarter-wave plate 623 , its polarization state is changed from linear vertical polarization to right-handed circular polarization.

The circularly polarized light L ₄ ′ with a right-handed direction can be reflected by an object 630 outside the electronic device 6 (eg, a smartphone). The light L ₄ ′ will become circularly polarized light L ₄ ″ with a left-handed direction after being reflected by an object (such as the surface of the user’s face) 630. The circularly polarized light L ₄ ″ with a left-handed direction passes through the quarter-wave plate 623 And when it enters from the second surface 622 of the translucent plate 520, it will be converted into linearly polarized light L ₄ ″' with a horizontal direction.

The polarizer 206 covering the optical sensing area 204 can allow linearly polarized light with a horizontal direction to pass through. Therefore, the linearly polarized light L ₄ ″' in the horizontal direction can pass through the polarizer 206 and reach the optical sensing area 204 to be sensed. The photodetector 203 can further convert the light L ₃ ″′ into an electrical signal after receiving it .

The arrangement of the polarizer 205 , the polarizer 206 and the quarter-wave plate 623 enables the electronic device 6 to receive light from the light source 202 and reflected by an external object 630 . The above arrangement can prevent the electronic device 6 from being affected by crosstalk without a shielding cover. Since there is no light-shielding cover, compared with the prior art, the volume of the optical module 60 or the electronic device 6 can be greatly reduced, the complexity of the process and the cost of manufacturing the optical module can be reduced. In addition, since the infrared absorbing layer does not need to be manufactured by the screen printing technology as in the prior art, the pollution and manufacturing cost caused by the screen printing technology can be reduced.

The above-mentioned embodiments are only for illustrating the principles and effects of the present invention, but are not intended to limit the present invention. In addition, the words "may have", "may include", "may use" and other words used above are not intended to limit the present invention. Those skilled in the art of the present invention can still make many changes and modifications without departing from the teaching and disclosure of the present invention. Accordingly, the scope of the present invention is not limited to the disclosed embodiments but includes other changes and modifications without departing from the invention, which are covered by the appended claims.

Claims (37)

1. An optical module, comprising: a carrier having a first surface; a light source located above the first surface; a light detector located above the first surface; and A first polarizer, the first polarizer is located on the light detector, wherein the polarization direction of the light emitted by the light source and the polarization direction of the light passing through the first polarizer are substantially perpendicular to each other. 2. The optical module according to claim 1, wherein the light source is a vertical cavity surface emitting laser (VCSEL). 3. The optical module according to claim 1, further comprising a second polarizer located on the light source, wherein the polarization direction of the light passing through the second polarizer is the same as that of the light passing through the first polarizer. The polarization directions of the light of a polarizer are substantially perpendicular to each other. 4. The optical module of claim 1, wherein the light detector has at least one optical sensing region, and wherein the first polarizer covers the at least one optical sensing region. 5. The optical module of claim 3, wherein the light source has at least one light emitting region, and wherein the second polarizer covers the at least one light emitting region. 6. An optical module, comprising: a carrier having a first surface; a photodetector having an upper surface and an optical sensing area located on the upper surface, the photodetector being located on the first surface; a light source located on the upper surface; and a first polarizer covering the optical sensing area, Wherein the polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer. 7. The optical module of claim 6, wherein the light source is a vertical cavity surface emitting laser. 8. The optical module according to claim 6, further comprising a second polarizer, the second polarizer is located on the light source, wherein the polarization direction of the light passing through the second polarizer is the same as that of the light passing through the first polarizer The polarization directions of the light of a polarizer are substantially perpendicular to each other. 9. The optical module according to claim 6, wherein the first polarizer completely covers the optical sensing area. 10. The optical module of claim 8, wherein the light source has at least one light emitting region, and wherein the second polarizer covers the at least one light emitting region. 11. An electronic device comprising: An optical module according to any one of claims 1 to 10; and A light-transmitting plate, the light-transmitting plate has opposite first and second surfaces, and the first surface of the light-transmitting plate faces the first surface of the carrier. 12. The electronic device according to claim 11, wherein the light-transmitting plate comprises glass. 13. The electronic device according to claim 11, wherein a quarter-wave plate is disposed on one of the first surface and the second surface of the light-transmitting plate. 14. The electronic device according to claim 11, wherein the first light emitted from the light source is in a first polarization state, and the first light is converted into a second polarization state after leaving the second surface of the light-transmitting plate. A polarization state, the first polarization state being different from the second polarization state. 15. The electronic device of claim 14, wherein the first polarization state is linear polarization and the second polarization state is circular polarization. 16. The electronic device according to claim 14, wherein a quarter-wave plate is disposed on the second surface of the transparent plate. 17. The electronic device according to claim 14, wherein the first light is reflected by an object after leaving the second surface of the light-transmitting plate to have a third polarization state, and the polarization direction of the third polarization state is the same as that of The polarization direction of the second polarization state is opposite, and the first light enters the light-transmitting plate from the second surface of the light-transmitting plate after being reflected by the object, and passes through the first light of the light-transmitting plate. A surface exits in a fourth polarization state, the third polarization state being different from the fourth polarization state. 18. The electronic device of claim 17, wherein the third polarization state is circular polarization and the fourth polarization state is linear polarization. 19. The electronic device according to claim 17, wherein the polarization direction of the first light in the fourth polarization state is substantially perpendicular to the polarization direction of the first light in the first polarization state . 20. A method of manufacturing an optical module, comprising: providing a carrier having a first surface; placing a light detector over the first surface; placing a light source above the first surface; and placing a first polarizer on the photodetector, Wherein the polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer. 21. The method of claim 20, further comprising electrically connecting the light source and the light detector with the carrier. 22. The method of claim 20, wherein the light source is a vertical cavity surface emitting laser. 23. The method of claim 20, further comprising placing a second polarizer on the light source, wherein the polarization direction of light passing through the second polarizer is different from that of light passing through the first polarizer. The polarization directions are substantially perpendicular to each other. 24. The method of claim 20, wherein the photodetector has at least one optical sensing region, and wherein the step of placing the first polarizer on the photodetector comprises placing the first A polarizer is positioned over the at least one optical sensing region of the photodetector. 25. The method of claim 23, wherein the light source has at least one light emitting region, and wherein the step of placing the second polarizer on the light source comprises covering the at least one light emitting region with the second polarizer. a luminous area. 26. The method of claim 23, wherein the first polarizer and the second polarizer are composed of a heat resistant material. 27. The method of claim 23, wherein the first polarizer and the second polarizer comprise metal. 28. The method of claim 23, further comprising covering the light source, the light detector, the first polarizer, the second polarizer, and at least part of the first polarizer of the carrier with a transparent material. surface. 29. A method of manufacturing an optical module, comprising: providing a carrier having a first surface; placing a photodetector on the first surface, the photodetector having an upper surface and an optical sensing region located on the upper surface; placing a light source on the upper surface of the photodetector; and placing a first polarizer over the photodetector and covering the optical sensing region, Wherein the polarization direction of the light emitted by the light source is substantially perpendicular to the polarization direction of the light passing through the first polarizer. 30. The method of claim 29, further comprising electrically connecting the light source and the light detector with the carrier. 31. The method of claim 29, wherein the light source is a vertical cavity surface emitting laser. 32. The method of claim 29, further comprising placing a second polarizer on the light source, wherein the polarization direction of light passing through the second polarizer is different from that of light passing through the first polarizer. The polarization directions are substantially perpendicular to each other. 33. The method of claim 29, wherein the step of placing a first polarizer over the photodetector includes completely covering the optical sensing region with the first polarizer. 34. The method of claim 29, wherein the light source has at least one light emitting region, and wherein the step of placing the second polarizer on the light source comprises covering the at least one light emitting region with the second polarizer. a luminous area. 35. The method of claim 32, wherein the first polarizer and the second polarizer are composed of a heat resistant material. 36. The method of claim 32, wherein the first polarizer and the second polarizer comprise metal. 37. The method of claim 32, further comprising covering the light source, the light detector, the first polarizer, the second polarizer, and at least part of the first polarizer of the carrier with a transparent material. surface.